New studies on Ground Zero search and rescue dogs could shed light on whether dangerous toxins were harmful to animals and humans alike.

So far, rumors about the failing health of the dogs have been put to rest.

“There have been no problems that we can link to the work related to the 9/11 attacks,” said veterinarian Cynthia Otto, investigator for a University of Pennsylvania study being funded by the American Kennel Club Canine Health Foundation.

Still, while conducting searches without protective masks, the dogs were exposed to high levels of lead, mercury, PCBs and other potentially hazardous compounds, Otto said.

The Penn research team will follow about 100 search dogs for more than three years, testing them for a variety of toxins.

“Dogs are affected by many of the same diseases, including cancer, as people,” said Otto. “The dogs’ shorter life span will potentially allow us to see adverse affects . . . on the canine rescue workers before they become apparent.”

At least six dogs who worked at Ground Zero have died. Four of those dogs, ages 10 to 13, were felled by cancer. Doctors said the deaths were not related to the dogs’ work at Ground Zero.

Along with that study, Iams Pet Imaging Center in Vienna, Va., is studying rescue pooches for cancer.

Over the next five years, 12 dogs – six from the Pentagon site and six from the WTC site – will be scanned by MRI to see if they’ve developed nasal carcinoma. A third study will look at 27 NYPD dogs.